Method and system for evaluating an assumed wave propagation speed in a medium

Abstract

The invention relates to a method of evaluating an assumed wave propagation speed in a medium, the medium being associated with spatio-temporal signal data, wherein the method comprises: evaluating (e) the assumed wave propagation speed based on phase properties of the spatio-temporal signal data.

1 . A method of evaluating an assumed wave propagation speed in a medium, the medium being associated with spatio-temporal signal data, the method comprising:
 evaluating assumed wave propagation speed based on phase properties of the spatio-temporal signal data.   
     
     
         2 . The method according to  claim 1 , wherein the spatio-temporal signal data comprises one of pre-beamformed spatio-temporal signal data and radiofrequency data. 
     
     
         3 . The method according to  claim 1 , wherein the phase properties comprise at least one of:
 signs,   phases,   a sign proportion,   phase intervals,   phase evolution states, and   proportions of phase properties.   
     
     
         4 . The method according to  claim 1 , further comprising:
 determining a figure of merit of the assumed wave propagation speed based on the phase properties,   wherein evaluating the assumed wave propagation speed is based on the figure of merit.   
     
     
         5 . The method according to  claim 4 , wherein the figure of merit is determined by using a predefined function G, the predefined function G being at least one of:
 a function G(x) that is symmetric about the axis x=50%, configured to one of maximize at x=50% and minimize at x=0% and x=100%, and to minimize at x=50% and maximize at x=0% and x=100%.   a bell-shaped function,   a normal distribution function, and   a negative Shannon entropy function.   
     
     
         6 . The method according to  claim 1 , wherein the spatio-temporal signal data are associated with a predefined spatial region in the medium. 
     
     
         7 . The method according to  claim 1 , further comprising:
 determining a subset of the spatio-temporal signal data as a function of a predefined spatial region in the medium and the assumed wave propagation speed,   wherein the assumed wave propagation speed is evaluated based on the subset.   
     
     
         8 . The method according to  claim 7 , wherein the subset comprises sections of the oscillating signals, wherein the sections are selected with respect to each other as a function of the spatial region and the assumed wave propagation speed. 
     
     
         9 . The method according to  claim 6 , wherein the method is iterated, in parallel or in series, for a plurality of subsets, each one being associated with a different spatial region in the medium,
 wherein the assumed wave propagation speed is evaluated based on figures of merit of the plurality of subsets.   
     
     
         10 . The method according to  claim 9 , wherein at least one of:
 the assumed wave propagation speed is evaluated based on figures of merit of selected subsets which are above a predefined threshold, and   the assumed wave propagation speed is evaluated based on weighted figures of merit according to a predefined weighting function.   
     
     
         11 . The method according to  claim 1 , wherein the method is carried out for a plurality of different assumed wave propagation speeds, and wherein the method further comprises:
 estimating an actual wave propagation speed in the medium based on the assumed wave propagation speed having the best figure of merit.   
     
     
         12 . The method according to  claim 1 , further comprising:
 adjusting the assumed wave propagation speed, as a function of the figure of merit,   wherein the method is iterated, such that the figure of merit is increased, wherein the method comprises in each iteration an adjusted wave propagation speed.   
     
     
         13 . The method according to  claim 12 , wherein at least one of:
 evaluating the assumed wave propagation speed comprises comparing the figure of merit with a predefined threshold,   the method is iterated until the figure of merit is above a predefined threshold, and   the method further comprises: estimating an actual wave propagation speed in the medium, based on the assumed wave propagation speed having the best figure of merit.   
     
     
         14 . The method according to  claim 1 , wherein the plurality of signals is received by a respective plurality of transducer elements. 
     
     
         15 . The method according to  claim 1 , further comprising before determining one of the subset the figure of merit:
 transmitting a pulse into the medium, and   receiving in response the plurality of signals from the medium.   
     
     
         16 . A method of estimating a wave propagation speed in a medium, comprising a method according to  claim 11 . 
     
     
         17 . A computer program comprising computer-readable instructions which when executed by a data processing system cause the data processing system to carry out the method according to  claim 1 . 
     
     
         18 . A system for evaluating an assumed wave propagation speed in a medium, the medium being associated with spatio-temporal signal data, wherein the system comprises a processing unit configured to:
 evaluate the assumed wave propagation speed based on the spatio-temporal signal data.   
     
     
         19 . The method of  claim 2 , wherein the spatio-temporal signal data comprises at least one of a plurality of oscillating signals and periodic signals received from the medium. 
     
     
         20 . The method of  claim 2 , wherein the spatio-temporal signal data comprises sections of the plurality of oscillating signals.